Massive climatic disturbances are wreaking havoc with the planet - underwater volcanic eruptions, tidal waves crashing over whole cities and snowstorms burying entire countries-and even the assemblage of the Ultimate U's mightiest is no match for this worldwide destruction! Featuring Spider-Man, the Fantastic Four, the X-Men, the Ultimates, the Hulk and more, find out whose lives are at stake in this defining moment of truth for the Ultimate Universe.